package bootstrap

import (
	"errors"
	"math"
	"sort"
	"strings"
	"time"

	"proxy-pool/internal/adapters/providerapi"
	"proxy-pool/internal/config"
	"proxy-pool/internal/controller/pool"
	controllerProvider "proxy-pool/internal/controller/provider"
)

var ErrProviderRuntime = errors.New("invalid Provider runtime configuration")

func newProviderFleet(configuration *config.Config, opened ports) (*controllerProvider.Fleet, error) {
	if configuration == nil {
		return nil, ErrProviderRuntime
	}
	names := make([]string, 0, len(configuration.Upstreams))
	for name, upstream := range configuration.Upstreams {
		if upstream.Enabled {
			names = append(names, name)
		}
	}
	if len(names) == 0 {
		return nil, nil
	}
	builder, err := providerRuntimeBuilder(opened)
	if err != nil {
		return nil, err
	}
	sort.Strings(names)
	runtimes := make([]*controllerProvider.UpstreamRuntime, 0, len(names))
	for _, name := range names {
		runtime, err := builder(name, configuration.Upstreams[name])
		if err != nil {
			return nil, err
		}
		runtimes = append(runtimes, runtime)
	}
	return controllerProvider.NewFleet(runtimes...)
}

type buildUpstreamRuntime func(string, config.Upstream) (*controllerProvider.UpstreamRuntime, error)

func providerRuntimeBuilder(opened ports) (buildUpstreamRuntime, error) {
	if nilInterface(opened.coordinator) || nilInterface(opened.activity) || nilInterface(opened.credentials) {
		return nil, ErrProviderRuntime
	}
	results := opened.providerResults
	if nilInterface(results) {
		results = discardProviderResults{}
	}
	return func(name string, upstream config.Upstream) (*controllerProvider.UpstreamRuntime, error) {
		upstream.Enabled = true
		mapped, err := providerRuntimeConfig(name, upstream)
		if err != nil {
			return nil, err
		}
		adapter, err := providerapi.NewHTTPAdapter(upstream.API, upstream.Fetch, nil)
		if err != nil {
			return nil, err
		}
		parser, err := providerapi.NewTemplateParser(name, upstream, opened.credentials)
		if err != nil {
			return nil, err
		}
		return controllerProvider.NewUpstreamRuntime(mapped, controllerProvider.UpstreamRuntimeDependencies{
			Coordinator: opened.coordinator,
			Inventory:   opened.activity,
			Adapter:     adapter,
			Parser:      parser,
			Activity:    opened.activity,
			Results:     results,
		})
	}, nil
}

func providerRuntimeConfig(
	upstreamID string,
	upstream config.Upstream,
) (controllerProvider.UpstreamRuntimeConfig, error) {
	if strings.TrimSpace(upstreamID) != upstreamID || upstreamID == "" || !upstream.Enabled ||
		upstream.Fetch.EstimatedIPsPerCall <= 0 || upstream.Capacity.MaxConcurrencyPerProxy <= 0 ||
		upstream.Pool.MaxSize > config.MaximumPoolSize ||
		int64(upstream.Fetch.EstimatedIPsPerCall) > controllerProvider.MaximumCoordinationInteger ||
		int64(upstream.Fetch.MaxInFlight) > controllerProvider.MaximumCoordinationInteger ||
		int64(upstream.Fetch.MaxTotal) > controllerProvider.MaximumCoordinationInteger ||
		int64(upstream.Fetch.EstimatedIPsPerCall) > math.MaxInt64/int64(upstream.Capacity.MaxConcurrencyPerProxy) {
		return controllerProvider.UpstreamRuntimeConfig{}, ErrProviderRuntime
	}
	expectedSlots := int64(upstream.Fetch.EstimatedIPsPerCall) * int64(upstream.Capacity.MaxConcurrencyPerProxy)
	return controllerProvider.UpstreamRuntimeConfig{
		Provider: controllerProvider.Config{
			UpstreamID:             upstreamID,
			RequestInterval:        time.Duration(upstream.Fetch.RequestInterval),
			Timeout:                time.Duration(upstream.Fetch.Timeout),
			MaxAttempts:            upstream.Fetch.MaxAttempts,
			MaxInFlight:            upstream.Fetch.MaxInFlight,
			MaxTotal:               int64(upstream.Fetch.MaxTotal),
			MaxSize:                upstream.Pool.MaxSize,
			TTL:                    time.Duration(upstream.Lifecycle.TTL),
			AllocationSafetyMargin: time.Duration(upstream.Lifecycle.AllocationSafetyMargin),
			Retry: controllerProvider.RetryConfig{
				Initial: time.Duration(upstream.Fetch.Retry.Initial),
				Max:     time.Duration(upstream.Fetch.Retry.Max),
				Jitter:  upstream.Fetch.Retry.Jitter,
			},
		},
		ReconcilePolicy: pool.ReconcilePolicy{
			MinimumAvailableSlots: upstream.Refill.MinimumAvailableSlots,
			TargetAvailableSlots:  upstream.Refill.TargetAvailableSlots,
			ExpectedPerFetch:      upstream.Fetch.EstimatedIPsPerCall,
			ExpectedSlotsPerFetch: expectedSlots,
			SafetyMargin:          time.Duration(upstream.Lifecycle.AllocationSafetyMargin),
		},
		ReconcileInterval: time.Duration(upstream.Refill.ReconcileInterval),
	}, nil
}

type discardProviderResults struct{}

func (discardProviderResults) Record(controllerProvider.Result) {}